Adult lake sturgeon movements associated with the large rivers of Green Bay, Lake Michigan

GBSTG

October 2005 - October 2020

The lake sturgeon population in Green Bay has suffered from over-exploitation, habitat destruction (including fish passage issues), and water pollution. The Wisconsin Department of Natural Resources (WDNR) Lake Michigan Integrated Fisheries Management Plan and the WDNR and Michigan DNR Menominee River Fisheries Management Plan advocate for the restoration of naturally recruiting lake sturgeon population in Green Bay and its tributaries, including the Menominee River. Lake Sturgeon is a high priority species for the agencies around Lake Michigan. The WDNR and other cooperators are taking great strides towards understanding the lake sturgeon population in Green Bay and its major tributaries. WDNR and other agencies have taken action to assess related sturgeon fisheries including an understanding of the genetic stock analysis and movements in Green Bay rivers. Michigan and Wisconsin have enhanced the lake sturgeon populations of Green Bay and its major tributaries through appropriate stocking (streamside rearing units at Whitefish and Cedar rivers) and recently imposed new conservative sport harvest regulations that have reduced angler harvest by 95%. Natural stocks occur in the major west shore tributaries of Green Bay including the Menominee, Peshtigo, Oconto and Fox rivers. Hydroelectric dams on each river prevent adult lake sturgeon from utilizing the entire available spawning habitat in these rivers which results in reduced recruitment success because cohorts are not able to fully develop in these river systems before entering Green Bay. It is imperative that management agencies evaluate the current status of lake sturgeon populations in Green Bay and advance research on the interactions of these stocks related to the west shore tributary spawning populations. Therefore, we're using two techniques to describe the movement and spawning fidelity of lake sturgeon to Green Bay rivers. We inserted acoustical V16 Vemco tags into 20-30 adult sturgeon at known spawning sites on each river for a total sample size of 117. The tags are active through at least 2025. We have 3-5 fixed receivers in each river to continuously monitor directional movement of the tagged sturgeon. We're also collecting tissue samples from each sturgeon. We'll be able to compare and contrast direct evidence of tagged sturgeon movement versus indirect genetic assignments to determine spawning fidelity.

• Describe stock structure of Green Bay lake sturgeon populations through expanded assessments.
• Further examine spawning river fidelity and movement for spawning stocks along Green Bay’s large west shore tributaries (Menominee, Peshtigo, Oconto, and Fox Rivers).
• Develop genotypic assignments for a subsample of adult sturgeon.
• Determine current spawning adult abundance to examine recent trends.
• Describe subsequent movements of spawning sturgeon

• A better understanding of the fidelity of spawning lake sturgeon to Green Bay rivers,
• Improved spawning population estimates for each river, and
• Expanded population assignments for individual lake sturgeon in Green Bay.
• Multiple year movement patterns of tagged sturgeon

• Christopher Long (Wisconsin Department of Natural Resources) - Christopher.Long@Wisconsin.gov
• Kim Scribner (Michigan State University)
• Ed Baker (Michigan Department Of Natural Resources)
• Robert Elliott (United States Fish And Wildlife Service)

• United States Fish and Wildlife Service
• Michigan Department of Natural Resources
• Michigan State University
• University of Wisconsin Stevens Point

• Wisconsin Department of Natural Resources
• United States Fish and Wildlife Service
• Great Lakes Fishery Trust